Filament clamping device for an automatic mounting machine



L. L. ARMSTRONG E'IAL 2,783,783

Margh 5, 1957 FILAMENT CLAMPING DEVICE FOR AN AUTOMATIC MOUNTING MACHINEFiled March 9, 1953 INVENTORS z. z fleMs/vw/v ATTORNEY United StatesPatent" P FILAMENT CLAMPING DEVICE FOR AN AUTOMATIC MOUNTING MACHINE LawLamar Armstrong and Houston D. Carson, Little Rock, Ark., assiguors toWestinghouse Electric Corporation, East Pittsburgh, Pa., a corporationof Pennsylvania Application March 9, 1953, Serial No. 341,308 2 Claims.or. 140-7145 The present invention relates to the manufacture ofincandescent lamps and, more particularly, to a coil clamping device forautomatic filament mounting machines.

In the automatic mounting of incandescent lamp filaments, particularlythose for lamps of higher wattage, the larger filaments, for example,coiled coil, employed therein are inherently brittle. This brittlenessresults in excessive lamp and mount shrinkage due to filament or coilleg fractures in the filament lead clamps during the automatic filamentfeeding and clamping operation. The leg or legs of the filament breakeither immediately during the clamping operation, or later in the lampfabrication between the sealing operation and final inspection. It isalso possible that some lamps having fractured coils get into packedproduction, thus constituting a serious quality problem.

Many attempts, such as the rejection of an entire lot of brittlefilaments, have been employed in the past to eliminate this qualityproblem. Even after an expensive inspection operation such as this, themount shrinkage remains excessive at a figure of fifty to one hundredmounts per day.

The mounting of a coiled coil filament is conventionally accomplished onan automatic mounting machine having a plurality of lamp stem heads, forexample 20, carried on a carrier or turret which is indexable fromstation to station. At station 1 a stem, positioned at the properheight, is delivered by a conveyor to a stem holding head. The leadwires may be spreadat station 2, trimmed to length at station 3 andflattened at station "4. At station 5 the coil clamping hooks are formedin the downward depending extremities of the lead wires. A coiled coilis delivered by automatic transfer means at station 6 and clamped in thehooks formed in the ends of the lead wires. It will be understood thatthe above mentioned fractures of the coil occurs at station "6, the coilfeeding and clamping station. The leads, carrying the filament, arepushed backwardly at station "7 so that the leads pass behind theprotective covering of a bathe which extends from stations "8 to 12, thearbor heating and plasticizing stations. The end of the arbor ispreheated at stations "8 and "9 and a button is preformed thereon atstation 10. Oxygen fires at station 11 raise the temperature of thepreformed arbor button to the proper molding temperature. A plurality ofsupport wires, for example three, are horizontally inserted in theplastic button at station 12. The center support wire is wiped (that ismoved downwardly) at station 13. At station 14 the lead wires are pushedforward to their normal position and the ends of the three supports aresuitably pre-curled, or partially formed, in the shape of open hooks.The open hooks of the two horizontal supports may be clamped about thelead wires at station 15. At station "16 the center support wire ishooked about the filament and the mount is finally positioned axially atstation 17. If the mount is to be getter dipped, getter is applied atstation 18, and dried .and filament clamping station. device comprises astationary mounting. blocklZ, a, coil 2,783,783 Patented Mar. 5, 7

2 by suitable heating means at station 19. The finished mount is thenunloaded at station 20" onto a suitable conveyor and delivered to anautomatic sealing and exhaust machine. I

Hence, it has been found advantageous according to our invention toemploy two small heaters at station 6, the coil delivery and clampingstation, to blow the hot gases of combustion on the coils and clampsduring the clamping operation. These gas burners burn into funnelsappended thereto, for heating the hooks on the leads, the filamentcarried by the hooks, and the clamping block by conduction, convectionand radiation from the funnelled combustion gases during the clampingoperation. The desired amount of heat can be obtained by varying the gasand air mixture fed to the burners.

In its general aspect, the present invention has as its objective theelimination of the defects of prior art clamping devices for automaticincandescent lamp filament mounting machines.

A specific object of the present invention is an improved clampingdevice which reduces fractured coil shrinkage and improves lamp quality.

Another specific object is an improved clamping device comprising aclamping block for carrying a clamping block anvil thereon, a pair ofcoil clamping arms pivoted thereon, and a pair of heaters for blowinghot gases on the anvil, the lead wire coil clamps positioned on theanvil, the coil carried in the open clamps, and the coil clamping arms,to heat said parts to a desired temperature and thus prevent coilfracture during clamping.

A further object is a pair of directed heaters, each comprising a gasburner whose flame burns in a directed funnel projecting therefrom, fordirecting a portion of the gases of combustion onto the lead wireclamps, the I device of our invention at a filament feeding and filamentclamping station of an automatic filament mounting machine and showingthe delivery of a preformed stem into the coil clamping anvil.

- Fig. 2 is a fragmentary perspective view showing the delivery of anincandescent lamp filament into the open clamps of the lead-inconductors of the positioned stem of Fig; 1.

Fig. 3 is a perspective view of a mount having. a clamped incandescentlamp filament.

Fig. 4 is a sectional view of a delivery funnel for the burner employedby applicants to heat the clamping block anvil, lead-in wires, clampinganvil and clamping arms during the clamping operation.

Referring to Fig. 1 of the drawing, an improved filament clamping deviceof our invention for an automatic incandescent lamp mounting machine isdesignated by the reference numeral 1.0. This device is mounted, as bybrackets or other suitable means (not shown), on the stationary portionof the machine at the filament feeding Thisfilament clamping clampinganvil 14 carried on said bloclg'a coil clamping arm lever 15 pivotablymounted on said block-IZ-and carrying a pair of coil clamping arms 16.and 18, and-a coil heating means 20 mounted by means ofJbrackets 22ontheblocklz. W

The block 12 has an inverted L-shaped lower portion 24, the verticallonger side of which is employed for mounting on the stationary portionof the automatic incandescent lamp filament mounting machine (notshown).

The horizontal shorter portion of the lower portion 24 7 extendsforwardly, as viewedin Fig. 1, and has a bifurcated end 26 which isemployed for pivotally mounting the lever as hereinafter explained. Aninverted Lishaped upper portion 28 of the'block 12 has its horizontalanvil supporting siirface 30 extending rearwardly, when viewed in Fig.1, for supporting the anvil 14 thereon. This coil clamping block anvil14 is provided with suitable spaced, downwardly inclined, lead wireguide slots 32, and a vertical axial arbor guide groove 36 in theforward portion of said anvil.

Depending from the guide grooves 32 adjacent the outer wall of eachgroove is a pair of clamping anvil extensions 38 (Figs. 1 and 2) which]extend inwardly, when viewed in Fig. 1, from the grooves32. Theseextensions may have vertical guide grooves in their outer-faces for theguided reception therein of the open hooked ends of extremities 42 ofleading-in and supporting conductors 44 of a lamp stem 46. In additionto the conductors 44, the stem 46 (Figs. 1 and 3) is provided with anarbor 48 and anexhaust tubulation 49.

Each of the coil clamping arms 16 and 18 is provided with a bendingchisel 50 and 52 respectively (Figs. 1 and 2) onits upper extremityforcooperation with stationary clamping anvil extensions 38, ashereinafter explained. The chisels 50 and 52 each have a hook engagingglide slot (Fig. 2) cut in the forward face and are adjustably mountedon bifurcations 54 of the bifurcated upper end of the coil clamping arm.lever 15. This lever ,15 is pivotably mounted on a pin 58 extendingbetween the bifurcations of the bifurcated end portion 26 of the coilbending block 12.

Coil heating means Ihecoilheating means are adjustably mounted oneachside of the clamping anvil extensions 38 byrneans of hrackets ZZ,adjustably secured to the underside of the lower portion 24 of themounting block 12. Each of the heating means 20 may suitably comprise aburner60 to which a gas and air mixture is fed by means of asuitableinlet pipe 64. The heating ends of the burners 60 are suitably cappedwith funnels 68 fordirecting a portion of the combustion gases againstthe stationary clamping anvil extensions 38, to continuously maintainthese parts (by radiation, conduction and convection) at a desiredtemperature during the filament feeding and filament clamping operation.

' In Fig. 2 a transfer arm 72 of a filament feeding mechanism (notshown), provided with a filament carrying nest 74 on its free end, isshown (in its downward vertical travel between the bifurcations 54 ofthe lever '15) depositing a filament 76 in the open hooks 42 of theleads 44.

Operation shown in Fig. 1 stem holding jaws 78 ofa stem holding head(not shown) of the automatic mounting machine carries a stem 46 by meansof its arbor. 48.

These jaws 78, and hence the hooked extremities 42 of the stem leads 44move downwardly into the guide grooves 32 in the anvil 14 (on which thehooks 42 are closed), until the hooks 42 rest in the guide grooves ontheheated clamping anvil extensions 38.

It will beunderstood that simultaneously the lower extremity of thearbor 48 enters the axial guide ,slot 36 on the endof the anvil 14, thuspositioning the stem 46 fer the filament feeding and clamping operation.It will be further understood that the lever 15 and hence .the coilclamping arms 16 and 18 carrie'dthereon (as shown in Fig. l) are in thefilament loading positinn, namely,

the position furthest away from the heated extensions 38.

After the hooked extremities 42 of the leads 44 have been positioned onthe extensions 38, the transfer arm 72 passes through the bifurcations54 and the bending chisels 50 and 52 and deposits the filament 76 on theupturned hooks 42. The transfer arm 72 then continues downwardly throughthe bifurcations 54 of the lever 15 after delivery of the filament 76.

It will be understood that meanwhile during the tile mentfeedingoperation the hooked extremities 42 have been heated to the desiredtemperature by combustion gases emitted from the funnels 66 andconduction, con vection and radiation from the extensions 38. Further,in the matter of seconds, the now positioned filament 76 and its legsparticularly, become heated to the same desired temperature. At theappropriate predetermined time in the operating index cycle the lever 15and the hook guide grooves in the arms 16 and 18 carried thereon, aremoved forward by cam actuating means (not shown) into contact with theopen ends 42 of the leads 44. The arms 16 and 18 press the open ends ofthe hooked extremities around the filament legs thus locking or clamp-'in'g said heated and now ductile filament legs therebetween. I

I Although a preferred embodiment of our invention has been disclosed itwill be understood that modifications may be made Within the spirit andscope of the invention.

We claim:

1. A filament clamping device for an automatic mounting machinecomprising a mounting block, a filament leg clamping anvil mounted onsaid block and having readily heatable extensions for positioning thefilament leg carrying ends of a pair of lamp stem leads thereagainst, anoscillating filament leg clamping lever pivotably mounted on said blockfor simultaneously engaging and clamping each of said filament carryingends about a 98. Of a filamentcarried therein, and heating means mountedon said block adjacent said anvil in substantially axial alignment withsaid extensions and for ductilizing said filament carrying ends andfilament legs prior to and during filament leg clamping by conduction,radiation and convection.

2. A filament clamping device for an automatic mounting machinecomprising a mounting block, a filament leg clamping anvil mounted onsaid block and having readily heatable extensions for positioning thefilament leg carrying ends of a pair of lamp stem leads thereagainst, anoscillating filament leg clamping lever pivotably mounted on said blockfor simultaneously engaging and clamping each of said filament carryingends about a leg of a filament carried therein, and heating meansmounted on said block adjacent said anvil for ductilizing said filamentcarrying ends and filament legs prior to and during filament legclamping by conduction, convection andradiation, said heating meanscomprising a burner adjacent each of said filament carrying ends and aheat directing funnel appended thereto and in substantially axialalignment with said extensions.

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